1. Field of the Invention
This invention relates to a one-way clutch assembly utilized in the transmission or the like of an automobile or an ordinary industrial machine such as an agricultural machine, a construction machine or an industrial machine. More particularly, it relates to a one-way clutch assembly of the hermetically sealed type provided with a lubricant reservoir.
2. Related Background Art
A one-way clutch used in an automatic transmission or the like has an outer race and an inner race rotated relative to each other, and a plurality of torque transmitting members for transmitting torque between the outer race and the inner race mesh with the raceway surfaces of the outer race and the inner race to thereby transmit rotational torque only in one direction. Also, design is made such that the outer and inner races are idly rotated in the opposite direction.
Generally, almost all of one-way clutches used in automobiles, etc. were forcibly lubricated from the inner race side of the one-way clutch. Particularly in a one-way clutch of the outer race rotation type in which the outer race side is rotated, lubricant flies to the outer diameter side by a centrifugal force and the lubricant runs short on the inner diameter side on which slip occurs, and the wear of the one-way clutch is induced. Therefore, the one-way clutch of the outer race rotation type is forcibly lubricated, and a one-way clutch of the package type in which lubricant is packed has been regarded as being unsuitable for the outer race rotation type.
As an example of the prior art, there is a package type one-way clutch 50 with an oil reservoir shown, for example, in FIG. 5 of the accompanying drawings. This example is not of a type in which lubricant (grease) is enclosed in the interior or surrounding space of the one-way clutch 50 which is hermetically sealed from the outside, but is provided with an oil reservoir storing lubricant on the axial outer side of a one-way clutch unit.
As shown in FIG. 5, in the one-way clutch 50 of this kind, a driving force from a high-speed rotation motor, not shown, is transmitted by a belt 51, and a belt 52 is connected to an output shaft, not shown. The one-way clutch 50 comprises an inner race 57, an outer race 56 provided outside thereof, and a one-way clutch mechanism portion 55 for transmitting torque between the inner race 57 and the outer race 56.
Bearings 58 and 59 are provided on the axially opposite sides of the one-way clutch mechanism portion 55. Seals 60 and 61 are provided between the inner race 57 and its partner member. An oil reservoir 53 is provided on the axially outer side of the one-way clutch mechanism portion 55. When the high-speed rotation motor is rotated, the lubricant escapes to the outer race side due to a centrifugal force created by high-speed rotation and therefore, the exhaustion of the lubricant may occur particularly on the outer peripheral raceway surface of the inner race. In order to prevent this, a predetermined amount of lubricant is supplied from the outside to the oil reservoir 53 through an oil supply hole 54 and is stored in the oil reservoir 53.
In the prior-art one-way clutch 50 of the above-described construction, (liquid) lubricant is supplied to the bearings and the interior of the one-way clutch by the use of the centrifugal force created by the rotation of the one-way clutch. In this example, however, it is necessary to provide an oil reservoir occupying a great volume on the axially outer side of the unit and therefore, the mounting space has naturally become large, and it has been unavoidable that the number of parts become great.
As described above, in the one-way clutch of the outer race rotation type, the lubricant is scattered to the outer diameter side by the centrifugal force and therefore, the lubricant runs short on the inner diameter side on which the one-way clutch effects sliding and meshing engagement. Remarkable wear might occur to the various elements (a torque transmitting member, etc.) of the one-way clutch which effects sliding and meshing engagement on the surface on which the lubricant is absent. Particularly, a one-way clutch of the package type having lubricant enclosed therein has been regarded as being unsuitable for being used in outer race rotation.
It is actually difficult and not realistic to enclose 100% of lubricant in the space of the one-way clutch of the package type and therefore, the above-noted problems remain left to be solved.
Accordingly, it is an object of the present invention to provide a one-way clutch assembly in which the sliding portion and meshing portion of each element of the one-way clutch are filled with lubricant and the wear of each portion can be suppressed for sufficient lubricant film. It is also an object of the present invention to provide particularly a one-way clutch assembly suitable for the package type.
To solve the above-noted problems, the one-way clutch assembly of the present invention is a one-way clutch assembly comprising an outer race having a substantially annular inner peripheral raceway surface, an inner race radially spaced apart from the outer race and disposed concentrically therewith for rotation relative thereto, and having a substantially annular outer peripheral raceway surface, and a plurality of torque transmitting members disposed between the outer race and the inner race and engaged with the inner peripheral raceway surface and the outer peripheral raceway surface for transmitting torque between the inner and outer races, characterized by the provision of a lubricant reservoir extending from the diameter of the outer peripheral raceway surface of the inner race to the inner diameter side thereof.
When the outer race is rotated, the portion sandwiched between the inner peripheral raceway surface of the outer race of the one-way clutch assembly and the outer peripheral raceway surface of the inner race is provided with a lubricant reservoir for securing an amount of lubricant enough to be filled with lubricant flying to the outer diameter side by a centrifugal force on the inner diameter side from the raceway diameter of the inner race.
The lubricant stored in the lubricant reservoir goes toward the outer diameter side and fills the space between the raceway surfaces of the one-way clutch assembly when the centrifugal force of the rotation of the outer race is applied. A similar action also takes place in the case of a centrifugal force created around the inner race by the rotation of the inner race. When the inner race is rotated simultaneously with the rotation of the outer race, an action similar to that only in the case of the rotation of the outer race takes place.